The Center on Airborne Organics was established at the California Institute
of Technology (Caltech), Massachusetts Institute of Technology (MIT), and
New Jersey Institute of Technology (NJIT) to address air pollution problems.
The nation is now struggling to implement the provisions of the Clean Air
Act Amendments (CAAA) of 1990, particularly those targeted at controlling
tropospheric ozone and air toxics. Increased concern is being expressed
with the health effects of ultrafine particles and a significant fraction
of the CenterÔs resources is directed at fine particles, their generation,
attribution of their sources from ambient measurements, and their effects.
Costly emission control measures adopted to date have proved to be only
partially successful in controlling ozone in urban areas. Ozone concentrations
still exceed current standards in many areas despite the expenditures of
many billions of dollars over the past two decades. The problem of
air toxics is one that is posing many challenges in defining the magnitude
of the problem posed by the 189 chemicals listed in the CAAA and establishing
priorities for their control. Tiny carbonaceous particles continue
to decrease visibility and are implicated in human health effects.
There is, however, large uncertainty as to the size, composition, and source
of the particles of concern to human health.

The reason it is so difficult to reduce atmospheric concentrations of
organic pollutants is that the atmosphere contains an enormous variety
of organic compounds with widely differing characteristics and impacts
on health and the environment. The sources which emit them (or their
chemical precursors) are also numerous and include natural processes as
well as anthropogenic activities. The quantity and composition of
material emitted even by familiar sources such as cars is unclear.
Once emitted, material may change chemically or physically in the atmosphere,
further complicating the task of matching airborne pollutants and their
source(s). Given such complexities and uncertainties, it is difficult
to forecast how a given regulatory strategy will influence ambient air
quality.

To support the policy making process, the Center on Airborne Organics
draws on the talents of recognized leaders at Caltech, MIT, and NJIT in
the areas of sources and control, transport and transformation, and
monitoring and source attribution to address the following interrelated
activities:

developing and using improved techniques to sample and analyze emissions
from sources and material in the air,

determining how emitted material is transported and changed in the environment,

refining existing methodologies for source attribution by identifying critical
compounds and structures in airborne organics and their environmental stability,
and